1. Field of the Invention
The present invention relates to encapsulated activated carbon and a method of preparing the same to protect the structure of the activated carbon and preserve the odor absorbing capability of the activated carbon particles. Particularly, the present invention is directed to a polymer substrate and a method of forming the same upon melt processing using activated carbon particles encapsulated with a non-water soluble amorphous polymer.
2. Description of Related Art
Garbage waste is often a source of odor in a household. For example, odor can be generated from waste during storage in a trash container or waiting for disposal in a garbage bag. Odor from waste can be a nuisance and a variety of methods and products are known for managing the odor. For example, one known technique uses a scented formula to mask the odor. Such conventional methods and systems generally have been considered satisfactory for their intended purpose, although there remains a need for addressing malodors without the resulting scented affect.
Therefore, a method of managing odor generation remains highly desirable for home waste management. It is also desirable that the odor from the household waste be reduced with a simple and cost effective method.
Activated carbon is known for odor absorption due to its highly porous nature and has been used in a variety of other industries for years for various odor control applications. For example, activated carbon has been used in filtration blocks, filter packages and others. Activated carbon has been recognized as an excellent candidate for odor reduction in certain applications involving porous or textile materials because of its known odor absorption capability and relatively low cost and availability.
However, when activated carbon is blended with a molten polymer, the porosity is reduced due to penetration of polymer molecules in the activated carbon. As a result, the odor absorbing capability of the activated carbon is reduced as compared to the original powdery state. This constitutes a potential performance issue for activated carbon or any odor additives embedded in a bag structure where quick odor absorption is desirable. Therefore a method is needed to preserve and facilitate the odor absorbing capability of the activated carbon in melt processing.
As described in U.S. Pat. Nos. 3,992,558 and 4,265,960, encapsulation of particles is known for dispersion purposes. The process is well developed and open to practice. U.S. Patent Publication 2006/0,008,646 describes coating activated carbon with a removable or leachable material for wet processing. As evident from this related art, this processing requires a washing removal step that necessitates disposal of the waste wash, additional labor, and increased hygiene. While this process may be suitable for the textile industry, it is not applicable to polymer products or industries that utilize a melt processing process.
Thus there remains a need for an efficient and economic method and system for protecting the structure of the activated carbon and preserving the odor absorbing capability of the activated carbon particles upon melt processing.